Various types of feeds, such as poultry feeds and animal feeds, tend to agglomerate rather than remain divided into relatively small particles such as pellets, which are readily ingestible without further processing just prior to distributing such feeds for their intended purposes. It is well known in the art that the addition of certain powdery materials as a "flowing agent" to such feeds before such agglomeration occurs will generally promote retention of non-agglomerated particles. The flowing agents are effective because they comprise fine particulate matter and tend to remove excess moisture and oil from the meal particles which would otherwise promote agglomeration. Such flowing agents are useful for most types of feeds, including oilseed meals manufactured from soybeans, sunflowers, flax, canola, and the like.
The flowing agent additives, such as those added to soy bean meal, include bentonite, finely ground limestone, low quality clay or dirt products, and the like. While most of these flowing agent additives generally comprise approximately 0.5-5 per cent by weight of the feeds to which they are added, such flowing agents usually have negligible nutritional value.
Fortunately, a substantial source of waste materials exists from manufacturing sugar from sugar beets and sugar cane, which are capable of not only providing flowing agents for poultry and animal feeds but which have nutritional value and which provide an opportunity to recapture otherwise productive land which has fallen into disuse from the discarding of such waste materials.
Sugar is generally obtained from sugar beets or sugar cane. The manufacturing process generally involves sequentially washing and slicing the raw sugar beets or the sugar cane, followed by boiling in water. The resulting pulp mixture is then pressed to extract sugar juice from the pulp. The next step is to remove impurities from the sugar juice. This is generally accomplished by blending the sugar juice with a thick slurry, commonly referred to in the industry as "milk-a-lime". The milk-a-lime is produced by calcining high quality, high calcium content limestone in a lime kiln fired with petroleum coke to produce hydrated lime.
Two different processes have been used to utilize the milk-a-lime slurry to remove the impurities. The older process involves blending the slurry with the sugar beet juice and reincorporating the carbon dioxide driven off by the calcining process into the resultant mixture. The mixture of sugar juice and milk-a-lime is then diverted through a centrifuge filter which effectively separates the sugar water from the milk-a-lime, with the latter retaining substantially all of the impurities. The lime slurry is then transported to either a roll filter or a frame and grate press with the remaining lime residue then mixed with fresh water to form a mixture containing 18-30% solids, which is then sluiced out to a dewatering pond or lagoon where it typically sits for at least two years.
In a newer process, the lime slurry, after passage through the filter or the frame and grate press, is processed through a rinsing cycle to remove additional sugar from the lime. The resulting mixture, which is dewatered to 25-30% solids, contains less sugar, less protein, and is drier than the residue obtained from the older process, is generally conveyed to a dewatering stockpile.
Careful analysis has disclosed that approximately 98% of the particles contained in such solids will pass through a 200-mesh sieve and 95% will pass through a 325-mesh sieve, which is a size distribution range which is substantially similar to that observed for other flowing agents used for animal and poultry feeds. However, a significant attribute of such solids is that they typically comprise not only substantial amounts of calcium but also comprise carbohydrates and other nutrients (approximately 3%), both of which provide essential ingredients for animal feeds and poultry feeds. Although lime cake obtained from the newer process has fewer carbohydrate and other nutrients due to the extra rinsing cycle, the particulate size distribution range of both processes is substantially similar. Moisture content of lime cake generally ranges from 18-30%, with the lime cake obtained from the lime lagoons usually having a higher moisture content than that obtained from the dewatering stockpiles.
What is needed is an apparatus and a method whereby the spent lime in the lime lagoons and in the dewatering stockpiles can be made productive as a nutritional flowing agent for animal and poultry feeds and thereby also freeing up the associated underlying land for productive uses.